Shares in Finnish company Orion went on the slide this morning after the drugmaker announced it was discussing whether to carry out another clinical trial of its heart failure drug Simdax with partner Abbott Laboratories.

Simdax (levosimendan) is already on the market in more than 40 countries around the world, and Abbott licenses rights to the drug in the USA as well as certain other countries around the world such as the UK, France and Germany where the drug is not yet approved.

But two Phase III clinical trials of Simdax reported last year – SURVIVE and REVIVE II – failed to show a significant improvement in survival in patients with heart failure, although there were some trends towards clinical improvements in patients on the drug.

Abbott now wants Orion to carry out – and fund – an additional study of Simdax, suggesting that it does not believe it will be possible to secure Food and Drug Administration (FDA) approval with the current data. In Europe, the US drugmaker is in discussions with the Swedish regulatory authority, which will act as the reference member state for mutual recognition approval in the European Union.

“Although no definitive decision has been made, Abbott is introducing negotiations with Orion on the design, scope and financing of the possible study, with the proposal including Orion funding the trial,” said the Finnish firm in a statement.

Orion reported sales of Simdax of 4.3 million euros ($5.5m) in the first quarter of 2006, a 34% increase on the same period of 2005. For the whole of last year the company booked 13.7 million euros from the product.

Shares in Orion had slipped over 6% on the news to 16.40 euros in mid-morning trading today, on investor concerns that the negotiations could mean a significant delay for the product, particularly if it is decided that a full, Phase III trial will be needed to get Simdax back on track.